1. Field of the Invention
This invention relates to an improved package for holding and dispensing liquids under pressure. More particularly, it relates to such a package incorporating a novel poppet valve, to the poppet valve, to a novel integral poppet and biasing spring, and to a novel spring used to bias the poppet valve to a normally closed position. Most especially, it relates to such a spring, poppet and spring combination and valve especially adapted for use in a syphon package for holding and dispensing the liquids under pressure.
2. Description of the Prior Art
The extensive prior art pertaining to syphon seltzer water packages has been set forth in the first related application listed above. Briefly, until the inventions of the first three related applications, seltzer water was conventionally packaged in thick glass bottles with permanently attached heads. The bottles were filled through the heads, shipped to the consumer, used by the consumer and returned to the bottler for cleaning and refilling, all without removing the head from the bottle. In order to dispense the seltzer water through a syphon, pressures of about 90 pounds per square inch are required, substantially higher than for conventional carbonated beverages. Glass containers filled to such pressures are dangerous. This fact and the economics of the distribution process resulted in a decline in the syphon seltzer water business to the point that syphon seltzer water is available in only a few areas of the United States at the present time.
The inventions of the above related applications have, for the first time, made it practical to package syphon seltzer water in plastic bottles with the dispensing head separated from the bottles. The packages disclosed in the first three related applications include a normally closed valve in the neck of the containers. The bottles may be shipped in conventional distribution channels with twist-off caps, which the consumer removes and replaces with a reusable dispensing head which is used to open the valve in order to dispense the seltzer water from the package. Unlike conventional carbonated beverage containers, these packages and the higher pressures employed allow the seltzer water to remain pressurized until the container is emptied, so that the product does not go flat when the container is partly empty.
Such packages impose stringent requirements on the valves used in them. The valves must provide a hermetic seal, be extremely reliable in operation and very low in cost. In order to be suitable for their intended use, the valves must be capable of forming a reliable, hermetic seal at pressures of 100 pounds per square inch (p.s.i.) or more and at lower pressures, between about 40 p.s.i. and atmospheric pressure. This is because the pressure in such seltzer syphon packages must be at least 90 p.s.i. when the container is filled, so that sufficient pressure will remain in the container when it is almost empty to force the remaining liquid from the package. When the package is almost empty, a seal that is effective at the higher pressures may not be maintained at the lower pressures then present in the package. The development of the inventions in the related applications have resulted in further improvements in such packages and their valves.